Course description

A fallacy is a mistake in the support an argument gives its conclusion. This course examines common errors and more demanding patterns in language, probability, and formal logic. It explains each idea directly, works through examples, and distinguishes the mistake from a legitimate neighboring argument. The units group related patterns so you can see how they differ. Some labels overlap or have several names; the aim is to understand the reasoning, not inflate a list of terms. You will also study related errors in evidence and decision making where the same checks are useful. This is a substantial course intended for several sittings. Start with the introduction and move through the groups at your own pace. The final unit brings everything together: explain the gap, preserve what remains supported, and repair the argument. A fallacy name never establishes that a person is foolish or that their conclusion must be false.

Topics covered

• What fallacies are and why context matters
• Attacks on people, motives, and associations
• Distorting an argument and changing the question
• Authority, popularity, tradition, and novelty
• Emotions, threats, and desired conclusions
• Selected evidence and misleading comparisons
• Assumed answers, false choices, and missing proof
• Ambiguous language, parts, and wholes
• Vague boundaries, perfect ideals, and value judgments
• Mistakes about causes and consequences
• Probability, selected patterns, and past investment
• Changing standards to protect a claim

Prerequisites and next steps

This course belongs to Reasoning Foundations. Start with the first step, then work through each level in order before moving back to the path.